1. Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine, a printer and the like, and a process cartridge used in such an image forming apparatus.
2. Related Background Art
Nowadays, electrophotographic image forming apparatuses are widely used as copying machines, printers and the like, and, in such an image forming apparatus, an electrostatic image formed on a photosensitive member (image bearing member) is developed by a developing device as a toner image which is in turn transferred onto a transfer material and then is fixed to the transfer material, thereby obtaining an image.
For example, in such an apparatus, as shown in FIG. 4, a toner image formed on a photosensitive drum (photosensitive member) 51 is transferred, by a transfer charger (transfer means) 52, onto a transfer material S sent from a convey means 50, and then, the transfer material is conveyed, by a convey belt 53, to a fixing means 54, where the toner image is thermally fixed to the transfer material. Thereafter, the transfer material is discharged onto a discharge tray 55.
A flow of air within the apparatus includes an air flow directed toward a direction shown by the arrows P from above a charger (charge means) 56 and a developing device (developing means) 57, and an air flow directed from the transfer charger 52 toward a direction shown by the arrow R and forcibly directed by a suction fan 58 provided at the convey belt 53 toward a direction shown by the arrows Q and then toward a direction shown by the arrows S to be discharged out of the apparatus rearwardly.
The convey belt is elongated in a left-and-right direction and is greater than a space Y between the fixing means 54 and a cleaning means 59 (for removing and collecting residual toner on the photosensitive drum 51 after the toner image was transferred), and level of increase in temperature of an outer wall 59a of the cleaning means 59 causes no problem, and heat from the fixing means 54 does not heat toner and a cleaning blade in the cleaning means 59 excessively so as to cause any problem. Thus, in such an apparatus, any air flow was not passed through the space Y.
However, in the above-mentioned image forming apparatus, when the conveying distance of the convey belt 53 is decreased in order to make the apparatus more compact, the cleaning means 59 storing the toner collected from the photosensitive drum 51 approaches to a greater extent the fixing means 54, with the result that the temperature of the cleaning means 59 is increased by the heat from the fixing means 54 so that blocking of the collected toner may be generated.